1. Field of the Invention
The present invention relates to a timing control circuit. More particularly, the present invention relates to a timing control circuit with personal identification function.
2. Description of the Related Art
With the rapid development of multi-media technologies, image data is now transmitted mostly in digital format instead of analogue format. To keep up with modern lifestyle, the size and volume of video or image devices continue to reduce. Although the traditional cathode ray tube (CRT) display has good display quality and relatively low production cost, the bulkiness of electron tube structure renders the miniaturization and the reduction of power consumption difficult. Moreover, the presence of radiation is always a potential hazard to the eyes of the users. Consequently, with the maturity of photo-electronic and semiconductor fabrication techniques, many types of flat panel displays have been produced and become popular. Liquid crystal display (LCD) is one type of the flat panel displays that has many advantages including low operating voltage, radiation-free operation, light weight and small size. Hence, liquid crystal display has gradually replaced the conventional CRT to become one of the mainstream products in recent years.
FIG. 1 is a block diagram showing the internal structure of a conventional liquid crystal display device. As shown in FIG. 1, the liquid crystal display device includes a liquid crystal display panel 101 having a plurality of data lines DL and scan lines SL. A gate driving circuit 103 is coupled to the liquid crystal display panel 101 through the scan lines SL and a source driving circuit 105 is coupled to the liquid crystal display panel 101 through the data lines DL. The liquid crystal display device further comprises a timing control circuit 110. According to a video data DDATA, a clock signal CLK, a data enable signal DE, a horizontal synchronous signal HSYNCH and a vertical synchronous signal VSYNCH, the timing control circuit 110 controls the timing of the source driving circuit 105 and the gate driving circuit 103. Thus, the liquid crystal display panel 101 is able to output an image.
The timing control circuit 110 further comprises a driving control unit 112 and a video processor 114. The driving control unit 112 controls the timing of the gate driving circuit 103 according to the vertical synchronous signal (VSYNCH) so that each scan line SL is driven in sequence. Similarly, the driving control unit 112 controls the timing of the source driving circuit 105 according to the horizontal synchronous signal (HSYNCH) so that each data line DL is driven in sequence. The video processor 114 transmits video data DDATA to the source driving circuit 105 according to the clock signal CLK and the data enable signal DE. Furthermore, the video processor 114 controls the source driving circuit 105 to transmit the video data DDATA from each data line DL to the liquid crystal display panel 101 in sequence so that an image is displayed.
Due to the rapid development of liquid crystal display technologies, the range of the technology applications is increasing every day. At present, the common applications include mobile phones, personal digital assistants (PDA), liquid crystal display (LCD) monitors, LCD televisions, notebooks, tablet PCs and so on. Since most liquid crystal displays are light, slim, and portable, they can also be easily stolen. Due to the portability characteristic, an LCD device may be spotted by a thief at any minute if the user does not closely keep an eye on his/her property.